Apparatus for adhesively bonding surfaces



June 29, 1965 w. E. MEISSNER ETAL 3,191,360

APPARATUS FOR ADHESIVELY BONDING SURFACES 2 Sheets-Sheet 1 OriginalFiled April 10, 1961 June 29, 1965 w. E. MEISSNER ETAL 3,1

APPARATUS FOR ADHESIVELY BONDING SURFACES Original Filed April 10. 19612 Sheets-Sheet 2 United States Patent 3,191,360 APPARATUS FOR ADHESIVELYBONDING SURFACES William E. Meissner, Devon, Pa., and Gardiner Lane,

Darien, Conn; said Meissner assignor, by mesne assignments, to FMCCorporation, San Jose, Calif., a corporation of Delaware Originalapplication Apr. 10, 1961, Ser. No. 101,986, now Patent No. 3,151,427.Divided and this application Aug. 16, 1962, Ser. No. 217,406

12 Claims. (Cl. 53383) This application is a division of applicationSerial No. 101,986, filed April 10, 1961, now US. Patent 3,151,427.

The invention relates to an improved apparatus for adhesively bondingsurfaces to each other.

In adhesively bonding either planar surfaces, as for example inlaminating or package-sealing operations, or contoured or irregularsurfaces, an adhesive is applied to one or more surfaces to be bonded bya brush, spatula, transfer roll, spraying device or by actually dippingone or more of such surfaces in the adhesive itself. These conventionalmodes of adhesive application do not provide the necessary assurancethat an even and continuous distribution of adhesive will be applied toall areas of the surfaces to be coated, especially after extended usewhen drying of the adhesive and clogging of the applicator is oftenencountered. Accordingly, a primary object of this invention is toprovide a generally new or improved and more satisfactory apparatus forapplying adhesives to surfaces to be bonded, and particularly inapparatus which is suited for continuous bonding operations.

Another object is the provision of an improved apparatus for applying anadhesive, to one or more surfaces to be joined, in the form of a mass ofbubbles of tacky filmforming material.

Still another object is the provision of an apparatus for adhesivelybonding surfaces to each other wherein a mass of bubbles of tackyfilm-forming material is disposed between the surfaces to be joined andthen placed under pressure to distort and ultimately rupture the bubblesand provide a substantially uniform and unbroken layer of tackyfilm-forming material.

A still further and more specific object is to provide an apparatus foradhesively sealing conventional valve bags after filling thereof.

These and other objects and advantages of the invention will becomeapparent from the following description and accompanying drawing inwhich:

FIGURE 1 is a side view of one embodiment of the apparatus of thepresent invention, with a portion thereof being broken away;

FIGURE 2 is a longitudinal vertical section through a filling spout of avalve bag packaging apparatus having incorporated therein the adhesiveapplicator of the present invention;

FIGURE 3 is a transverse vertical section taken substantially along theline IIIIII of FIGURE 2;

FIGURE 4 is a shortened top view of a portion of the apparatus shown inFIGURE 2;

FIGURE 5 is a vertical section through the valve portion of the bagshown in FIGURE 2 just prior to sealing thereof; and

FIGURE 6 is a view similar to FIGURE 5 showing the bag valve in a sealedcondition.

In general, the present invention relates to adhesively bonding surfacesto each other by a mass of bubbles of tacky film-forming materialwherein the applied bubbles of adhesive material are distorted andruptured to provide a generally uniform and unbroken adhesive layer asthe surfaces are pressed together. Broadly, the apparatus of ice thepresent invention includes means for providing a tacky film-formingmaterial, means for dispersing the tacky film-forming material into aplurality of individual masses, and means for inflating such masses toprovide a plurality of adhesive bubbles.

In a more specific arrangement, apparatus for dispersing and inflatingtacky film-forming material into a plurality of adhesive bubbles isincorporated into a filling spout of a valve bag packaging machine forapplying a layer of adhesive bubbles to an adjacent surface of a bagvalve after the bag filling operation is completed. As the bag valve isurged into a closed position, as for example by movement of the bagcontents thereagainst, the adhesive bubbles of the applied layer aredistorted and ultimately ruptured to thus seal the bag valve in closedposition with a generally uniform and unbroken layer of tackyfilm-forming material. In accordance with the present invention,adhesive bonding of surfaces can be satisfactorily achieved by employinga single and relatively large inflated mass of tacky film-formingmaterial. A preferred procedure, however, is to eiiect bonding by usinga plurality of small bubbles of tacky filmforming material which areadapted to more readily enter into any folds or pleats in the surfacesbeing bonded and thus provide greater assurance of the formation of anunbroken adhesive layer as such bubbles are collapsed.

A wide variety of film-forming materials which are of a tacky oradhesive character when rendered plastic .or flowable may be employed inthe practice of the present invention. Preferred types include thesynthetic linear polymers of thermoplastic character and the elastomerictypes. Examples include vinyl resins, such as polyvinyl acetate,copolymers of vinyl chloride and vinyl acetate, copolymers ofacrylonitrile and vinyl acetate, polyacrylonitrile and copolymers ofacrylonitrile with vinyl chloride, vinyl acetate, methacrylonitrile, andso forth, polyethylene, linear superpolymers of the polyester of nylon(polyamide) type, polyvinyl butyral, polyvinyl alcohols, polyvinylethers; elastomeric types may include neoprene, polymers of chloroprene,copolymers of butadiene with styrene or acrylonitrile, polyisobutylene,and so forth. It is to be understood that the mentioning of theseparticular materials is not intended to limit the invention thereto butmerely to illustrate the wide variety of film-forming .material,theplasticizer or solvent is preferably non-reactive with the inflatingmedium. The cooling of the fused plastic mass, with or withoutplasticizers, is effected as the expanded bubbles of film-formingmaterial are distorted and ruptured to provide a continuous lining orcoating along the adjacent surfaces being joined.

Volatile solvents may be employed for dissolving or dispersing thefilm-forming material so that a mass thereof may be formed at roomtemperature and expanded, with the setting or coagulation of theexpanded bubble or bubbles, after application to the surfaces beingsealed, occurring by volatilization of the solvent. Known solvents andplasticizers may .be employed, the selection depending upon theparticular film-forming material to be used. Thus, acetone or dioxanemay be used for vinyl acetate or copolymers of vinyl acetate or vinylsmall masses.

into small masses.-

chloride or acrylonitrile. The concentration of the filmformingmaterial, when a solution thereof is used, is preferably as great aspossible and is limited only by the necessity that the plastic mass becapable of expanding under the pressure of the inflating medium, yet beof a reasonablyviscousand coherent plastic character so as to be capableof supporting its own weight.

The inflating medium may be air or other gas which is non-reactive withthe film-forming material or the materials being bonded. As heretoforementioned, the inflating medium is preferably heated when delivered intothe film-forming material to prevent premature setting thereof. Insealing large surfaces, it may be further desirable to effect bondingwith the surfaces themselves being heated or disposed within a heatedchamber.

The teachings of the present invention are applicable to adhesivelybonding surfaces of various construction which are formed of the same ordifferent materials. With surfaces of porous or permeable construction,the adhesive bonding material may serve an added function, such as amoisture or light or gas barrier, or as a stiffener for impartingrigidity to the bonded surfaces where flexible materials are employed.Further, while the present invention is applicable to bonding ofcontoured or irregular surfaces, for the sake of simplicity and ease ofdescription, the apparatus will hereafter be described as applied toadhesively bonding generally planar surfaces, such as encountered in'laminating of sheet materials or bag or sacksealing operations.

For a more detailed description of the invention, reference is madeinitially to FIGURE 1 of the drawing which illustrates one embodiment ofthe apparatus of the present invention. This particular apparatus is ofportable construction and preferably of a size which can be readily heldby one hand of an operator and easily moved relative to a surface forapplying an adhesive coating thereto. Basically, this apparatus includesa tubular housing 11, a screen 13 extending across one end of thehousing and secured thereto by a collar 15, a porous plug 17 disposedwithin the housing 1.1 and retained therein by the screen 13, a cap 19secured to the opposite end of the housing 11, and a pair of conduits 21and 23 which extend through and are secured to the end cap 19 by nuts2.5. The conduit 21 is connected to a source of tacky film-formingmaterial, not shown, which is preferably pumped through the conduit 21at a generally uniform rate concomitantly as the apparatus is set intooperation. The discharge end of the conduit 21 is preferably spaced fromthe porous plug 17 and the delivery of tacky film-forming material is soregulated as to provide a small head of tacky film-forming materialwithin the housing '1 1, as shown at 27. The conduit 23, on the otherhand, terminates adjacent to and preferably within the plug 17 and isconnected to a suitable supply 'of compressed gas, such as air, which ispreferably but not necessarily delivered as a rapidly pulsating flow.

. As heretofore mentioned, the plug 1-7 is of porous construction sothat the tacky film-forming material 27 may flow therethrough and bebroken up'into relatively The plug 17 may be comprised of granular,fibrous and/or cellular materials, as for example metal particles, metalor glass wools, cellulose, plastic or rubber sponge, etc. The porosityof the plug 17 may be readily controlled, as for example by selectingparticles of uniform or mixed sizes when granules are employed, byregulating the degree of compression applied to metal or glass wools, byselection of a sponge having voids of desired size, or by using theabove noted materials in different combinations with each other.

In the operation of the above described apparatus, tacky film-formingmaterial 2.7 delivered into the housing 1 1 flows through the porousplug 17 whereby it is broken As these masses of tacky film-formingmaterial approach the screen 13, they are subjected to compressed air orother .gas issuing from the conduit 23 and are thus inflated anddischarged through the screen 13 as a plurality of adhesive bubbles, asshown at 29. The portion of the porous plug 17 which extends across theend of the conduit 23 serves to effectively deflect the compressed gasdischarged therefrom along different directions and thus prevents thetacky film-forming material from being sprayed from the apparatus astiny droplets or globules. As a further precaution against suchoccurrence the compressed air may, if desired, be delivered as a rapidlypulsating flow. The inflation of the masses of tacky film-formingmaterial gene-rally occurs as the material approaches and passes throughthe screen 13 and thus the mesh or screen openings assist in regulatingthe sizes of the adhesive bubbles as they are formed.

The adhesive bubbles discharged from the apparatus described may becollected as a layer on one or more of the surfaces to be bonded. Asheretofore mentioned, the relatively small size of adhesive bubblesenables the same to more readily enter into folds and otherirregularities in the surfaces being joined. As the formation of adesired layer of adhesive nears completion, delivery of compressed airis continued momentarily after the supply of tacky film-forming materialhas been cut off. In this manner tacky film-forming material is removedfrom the screen 13 and the porous plug 17 adjacent thereto, and thusavoids undesired dripping therefrom. The

surfaces thus coated are then pressed together causing the adhesivebubbles which are interposed ther'ebetween to be gradually distortedinto a flattened condition and ultimately ruptured. As the surfaces arepressed together it will be apparent that the small adhesive bubbleswill be urged further into folds and other surface irregularities. Moreimportant, during this distortion from their original sphericalconfiguration to a flattened condition, the adhesive bubbles willprogressively line the surfaces with which they engage, and uponrupture, will provide a generally uniform and unbroken layer of tackyfilmfor-ming material between the surfaces.

The embodiment of the invention shown in FIGURES '26 is particularlydesigned for use in adhesively sealing conventional valve bags afterfilling thereof with granular or pulverant materials. Generally,conventional valve bag packaging apparatus, includes a filling spoutwhich is inserted into the valve opening of an empty bag after which thematerial to be packaged is delivered, as for example pneumatically or byscrew impeller. The bottom of the bag is normally supported by a bagchair which may be oscillated or otherwise vibrated to assist insettling the packaged material within the bag. After the bag has beenfilled with a predetermined amount of material, the bag is movedlongitudinally off the filling spout and tilted onto its side wherebythe movement of the packaged material within the bag urges the bag valveinto a closed position. Since with conventional apparatus the bag valveis not actually sealed in a closed position there is a tendency for thepackaged materials, and especially materials which are in a pulverant orpowdered form, to escape through the bag valve as the contents arevibrated or shifted within the bag as during handling and transit.

corner of the bag 35 is left unsealed during bag fabrication and islined with a sleeve 37 of paper or like material to provide a valvethrough which the bag may be filled.

With reference to FIGURE 2 of the drawing, the apparatus there disclosedincludes a filling spout 39 having an overhanging lip or deflector 41 atone end. A flange 43 is formed at the opposite end of the spout39 and isfixed to a material supply hopper 45 in alignment with a hopperdischarge opening 47. As shown in FIGURE 3 an arcuate plate 49 issecured, in fluid-tight relationship, to the top portion of the spout 39to provide a conduit 51 into which tacky film-forming material 53 isdelivered by a pipe 55. A plug 57 of porous material is disposed withinthe open end of the conduit 51 and is retained therein by a screen 59disposed'along an inclined plane.

The pipe 55 is connected with a suitable source, not shown, of tackyfilm-forming material which is preferably pumped at selectedpredetermined intervals as more fully described hereafter. Positionedconcentrically within the pipe 55 is a gas delivery conduit 61 which isconnected to a source of compressed gas, not shown, and opens into aheader 63. A series ofspaced gas discharge pipes 65 extend from theheader 63 and terminate adjacent to and preferably within the porousplug 57.

In the operation of this embodiment of the invention, an empty valve bag35 is initially disposed on the combined filling spout and adhesiveapplicator, indicated by the character 67. The overhanging lip 41 of thespout 39 facilitates rapid positioning of the bag 35 and, in addition,serves to direct the material being packaged away from the bag valve. Asshown in FIGURE 2, the member.

67 fits rather snugly within the bag sleeve 37 and, if desired,conventional means may be provided for preventing blow back of thematerial being packaged due to back pressure within the bag itself.

The material to be packaged is delivered from the hopper 45 and throughthe spout 39 in a conventional manner, as for example by an impeller orby being mixed or fluidized with an air stream. Once the desiredquantity of material is delivered into the bag 35, the filling operationis stopped after which the bag 35 is slidably removed from the member67.

During removal of the filled bag 35 from the member 67, compressed gas,preferably air, is delivered through the series of pipes 65 and into theporous plug 57. As described with reference to the apparatus of FIGURE1, the compressed gas serves to inflate the masses of filmformingmaterial in the pores of the plug 17 causing a plurality of adhesivebubbles to issue from the screened opening, as shown at 69.Concomitantly with the delivery of compressed air, tacky film-formingmaterial is pumped through the pipe 55 and into the conduit 51 tomaintain the plug 57 in a generally saturated condition.

As best seen in FIGURE 2, the inclined relationship of the screen 59serves to direct the adhesive bubbles 69 toward the adjacent portions ofthe bag sleeve 37, thus providing a layer 71 of adhesive bubbles thereonas the bag 35 is being continuously withdrawn from the member 67.Pumping of the tacky film-forming material through the pipe 55 isstopped as the left end of the bag sleeve '37, as viewed in FIGURE 2,approaches the screen opening of the conduit 51, with the delivery ofthe compressed air being stopped shortly thereafter. This pro cedureserves to reduce the amount of tacky film-forming material within theporous plug 57 and thus minimizes escape of the same after the adhesivebubble forming operation is completed. After the bag 35 is removed fromthe member 67, as shown in FIGURE 5, the filled bag is tilted onto itsright side, as viewed in 'FIGURE 5, whereby the packaged material shiftstherein to close the bag valve, as in conventional valve bag fillingoperations. As the opposite portions of the bag sleeve 37 are pressedtogether, the adhesive bubbles and layer 71 are distorted into flattenedpositions and ultimately ruptured, as heretofore described withreference to FIGURE 1, to thus provide a generally uniform and unbrokenadhesive coating therebetween.

In the operation of the above described apparatus, the compressed airmay be delivered to the plug 57 as a steady stream or as .a rapidlypulsating flow. The positions and number of gas delivery pipes 65 may,of course 6 be varied to suit particular operating conditions. Further,asuitable coating can be applied to the top surface of the overhanginglip 41 of the filling spout 39 to prevent adherence of the tackyfilm-forming material thereto.

Various changes and modifications may be made in practicing theinvention without departing from the spirit and scope thereof, and,therefore, the invention is not to be limited except as defined in theappended claims.

'forming material.

2. Apparatus for applying adhesive including a porous means, means fordelivering a tacky film-forming material to said porous means, and meansfor passing a gaseous medium into said porous means to urge saidfilmforming material therethrough as a plurality of individual massesand to inflate the same into a plurality of bubbles of tackyfilm-forming material.

3. Apparatus for applying adhesive including a container for tackyfilm-forming material, porous means positioned within an open end ofsaid container for dispersing the .tacky film-forming material into aplurality of individual masses as it passes therethrough, and means fordelivering a gaseous medium into said porous means to urge the tackyfilm-forming mate-rial therethrough and to inflate the individual massesthereof into a plurality of bubbles of tacky film-forming material.

4. Apparatus for applying adhesive including a tubular member, porousmeans positioned within one end of said tubular member, means at theopposite end of said tubular member for supplying tacky film-formingmaterial thereto and at least one pipe extending through said oppositeend of said container and terminating at least adjacent to said porousmeans for delivering a gaseous medium, whereby the tacky film-formingmaterial is urged through the porous means as a plurality of individualmasses and inflate-d into a mass of bubbles of tacky film-formingmaterial.

5. Apparatus as defined in claim 4 wherein said porous means includes amass of non-woven interlocking fibers, and a screen extending across theopen end of said tubular member.

6. Apparatus as defined in claim 4 wherein said porous means includes amaterial having a plurality of interconnected voids, and a screenextending across the open end of said tubular member.

7. Apparatus as defined in claim 4 wherein said pipe terminates withinsaid porous means.

'8. In a valve bag filling machine the combination comprising a fillingspout adapted to 'be inserted into the valve opening of a valve bag,means for delivering a material to be packaged to and through saidfilling spout, a conduit opening along an outer surface of said spout,means for supplying tacky film-forming material to said conduit, andmeans for discharging the tacky film-forming material from said conduitas a mass of expanded bubbles.

9. In a valve bag filling machine the combination comprising a fillingspout adapted to be inserted into the valve opening of a valve bag,means for delivering a material to be packaged to and throughsaid'filling spout, a conduit extending along the periphery of saidspout for containing tacky film-forming material, porous means disposedwithin the end of said conduit adjacent to the discharge end of saidspout, means for supplying tacky film-forming material to said conduit,and means for delivering a gaseous medium to said porous means forurging tacky film-forming material there- .through as individual massesand for inflating the same into a plurality of bubbles of tackyfilm-forming material.

10. Apparatus as defined in claim 9 wherein the dis charge end ofsaid'c'onduit terminates at a location spaced from the dis-charge end ofsaid spout and extends along a plane inclined at an acute angle withrespect to the adjacentsurf ace of said spout whereby the plurality ofbubbles are directed away from the conduit as they issue therefrom.

11. Apparatus as defined in claim 9 wherein said p0- rous means includesa screen disposed across the open end of said conduit and said means fordelivering said gaseous medium includes at least one supply pipe whichterminates within said porous means.

12. In a valve bag filling machine the combination comprising a fillingspout adapted to be inserted into the valve opening of a valve bag,means for delivering a material to be packaged to and through said[filling spout, a conduit opening along the outer periphery of saidspout for containing tacky film-forming material,

means for supplying tacky film-formingmaterial to said conduit, meansfor breaking the tacky film-forming material into individual masses asit is discharged from said conduit and means for inflating saidindividual masses of tacky film-forming material into a bubble form.

r References Cited by the Examiner UNI ED STATES PATENTS 72,907,15310/59 T-oles Q -Q. 53j383 X 3,097,584 7/63 Wright 1l8'2-66 X I FOREIGNPATENTS 457,419 11/36 Great Britain.

FRANK E. BAILEY, Primary Examiner.

TRAVIS S. MCGEH'EE, Examiner.

12. IN A VALVE BAG FILLING MACHINE THE COMBINATION COMPRISING A FILLINGSPOUT ADAPTED TO BE INSERTED INTO THE VALVE OPENING OF A VALVE BAG,MEANS FOR DELIVERING A MATERIAL TO BE PACKAGED TO AND THROUGH SAIDFILLING SPOUT, A CONDUIT OPENING ALONG THE OUTER PERIPHERY OF SAID SPOUTFOR CONTAINING TACKY FIL-FORMING MATERIAL, MEANS FOR SUPPLYING TACKYFILM-FORMING MATERIAL TO SAID